Updated COVID-19 vaccine guidelines from CDC indicate that even if recipients fail to get a booster dose within the recommended time frame, they have as long as 6 weeks after the initial injection to complete the immunization. The specified period between doses is 3 weeks for the Pfizer vaccine and 4 weeks for the Moderna product.

Mutations in the coronavirus are forcing drugmakers to change their plan of attack. Vaccines from Moderna and Pfizer-BioNTech, the only two authorized for emergency use in the United States, both offer protection against the U.K.

Corporate America is lending a helping hand to the country's COVID-19 vaccination drive, which has struggled with poor coordination, supply bottlenecks, and miscommunication in its early weeks. Chains such as CVS Health, Rite Aid, Walgreens, and Kroger are already active in vaccine distribution.

Unlike his predecessor, President Biden is embracing a more centralized strategy for managing the COVID-19 pandemic.

On January 21, his first full day in office, President Joe Biden will unveil his administration's playbook for ending the COVID-19 crisis. The 21-page national strategy houses seven broad goals, starting with regaining the public trust through regular briefings with CDC and other government scientists and public sharing of data.